Yes, St Louis did it before.
In the terrible pandemic of 1918.
The chart shows their success:
* Philadelphia downplayed it and held a parade in 1918
* St. Louis canceled gatherings and flattened the curve
pnas.org/content/104/18…
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It is open-access here pnas.org/content/104/18…
On my point above here is a key passage from this research.
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It wasn’t that deaths were just postponed.